Anode



A. B. GRIGGS Oct. 27, 1936.

ANODE Filed Jan. 5, 1955 INVENTOR. J/berl fin @ri' 6 BY M ATTORNE;

Patented Oct. 27, 1936 ANODE Albert B. Grlggs. ShakerHeights, Ohio. assignor to The Grasselli Chemical Company, Cleveland, Ohio, a corporation of Delaware Application January 1 Claim.

This invention relates to anodes, and is particularly directed to consumable anode units in the form of grooved, cylindr'aceous figures, which anode units are supported in a perforate, receptacle made of a material insoluble in a plating bath.

Those working in the art have found it desirable, under some circumstances, to employ composite anodes which comprise a perforate receptacle, which is insoluble in the plating bath, withm in which receptacle were placed soluble "anode units having the form of spheres or sticks. In the course of plating operations, more of the units were added to the receptacle as required. This practice has been none too satisfactory because a large amount of metal is required to fill the basket, and because the effective area of the anode tends to vary from the top towards the bottom of the solution.

It is an object of my invention to provide a 20 composite anode which employs such anode units that, within limits, the ratio of the weight of consumable metal to the effective anode area can be varied at will. A further object of my invention is to provide a composite anode which has a relatively constant effective area from top to bottom. Other objects will become apparent hereinafter.

I accomplish my objects by the use of grooved anode units in a perforate, insoluble receptacle. In operation such a receptacle is filled with the anode units, and the composite anode thus formed is used, in known manner, as an anode in electrodeposition. After a time, the anode units are dissolved and diminished in size, and it becomes necessary to add more anode units to the receptacle. After a considerable period, the anode units are of successively smaller size from the top to the bottom of the receptacle: the units lower in the receptacle having been in use for a longer period of time. I

A grooved anode unit has an area greater than an unmodified unit. The depth, shape, and number of grooves determine the area of a given figure, and, by varying the number and/or char- 5, 1935, Serial No. 505 (CI. 204-4) Figure 5 illustrates a modified form of anode unit, i Figure 6 shows another modified anode unit,

Figure '7 shows a further modified anode unit,

Figure 8 shows a still further modified anode 5 unit, and

Figure 9 shows a still further modified anode un Considering the illustrative embodiments of my invention in more detail; in Figure 1 there is seen 10 a preferred anode basket illustrated as containing a number of unused anode units. The anode basket includes a wire helix i which, as shown, has a substantially uniform pitch and has substantial spaces between its convolutions. The helix I is closed at its lower end by a cup 2. The wire helix I is welded to a strap 3 which isbent at its lower end to form a support 4. The wire helix i is welded to cup 2, and cup 2, in turn, is secured to support 4 by a bolt 5. The upper end of.strap 3 is bent to form a hook 6 which serves to support the basket in a plating bath.

The hook 6 is preferably attached to a bus bar, and an electric current is distributed from the bus bar thru'the strap 3, helix l, cup 2, and bolt 5. Anode units within the helix are thus electrically charged.

The basket is made of a metal, such as iron, steel, or lead, relatively insoluble in the plating bath in which it is to be used. The basket may, of course, be made in whole or in part of an insoluble, electrically non-conductive material, but in, this event, provision must be made for contacting the anode units with a source of current. The basket, similarly, may be isulated as by coating the portion which will contact the bath with rubber. In this event. a contact is preferably provided at the bottom of the basket by leaving the inner end of bolt 5 uncoated so that an electric 'current may be carried to the anode units thru 40 strap 3.

The form of some of my anode units may cause them to tend to stick in the basket. This is not particularly serious when the baskets have many exposed electrical contacts, and the units will readily continue their downward course if the basket be shaken. If the basket is made of an insulator, or is insulated, the sticking of an anode unit may break the electrical contact between it and the rest of the units. Worse yet, ifthe only 5 current source is at the bottom of the basket, an anode unit which sticks will .hold up all of the units above it, and they, likewise, will fail to receive current.

To minimize the tendency for the anode units manner. The upper ends of the wires are held in the proper relative positions by attachment to a ring 0. An angle bar Iii is fastened to the disc 8 and to the ring 9. The angle bar Ill terminates at its upper end in a hook 6. The basket may be suspended in a plating bath by means of the hook i.

The basket of Figure 2 may be made of any suitable material such as those above noted in connection with Figure 1. If the basket be all metal, the entire basket serves to distribute current to the anode units. If the basket be covered with an insulating material, the upper portion of disc 8 should be left uncoated so that a current may be carried from hook 6 thru angle bar III to the anode units. Similarly, if the basket be constructed of a non-conductor, some provision must be made for carrying an electric cur- I rent to the anode units.

The modified basket of Figure 3 difiers from the basket of Figure 2 in that the wires 1 are positioned as elements of an inverted, frustoconical figure. By making the basket larger at the bottom than the top, there is even less of a tend-- ency for anode units to stick. In the drawing, the extent of the increase in size from top to bottom is somewhat exaggerated for purposes of illustration. It will be readily understood that the basket of Figure 1 may be made larger at the bottom than at the top for the same purposes.

In the course of their downward travel the anode units become smaller and smaller. In order to retain the small units, and fragments, in the basket, it is desirable to position the wires 1 rather close together. The spaces between the convolutions of the helix i of Figure 1 should, similarly, not be too great. To avoid the use of too much material in the baskets, it may sometimes be desirable to make the spaces smaller near the bottom of the basket as by spacing the convolutions of helix i closer at the bottom, or, particularly in the baskets of Figures 2 and 3, as by the interpolation of short, vertical wires, by the use of a number of spaced turns of wire, woven, or encircling, the bottom portion of the vertical wires, or by the application of a circumferential strip of foraminous material on the lower portion of the basket.

The basket of Figure 1 is illustrated as containing a plurality of grooved anode units such as the one shown in Figure 4. The consumable unit of Figure 4 consists of a grooved cylinder. The four grooves extend longitudinally, and their shape, in section, resembles a V with semi-circular sides, as shown. The height of the figure is substantially equal to its greatest dimension in a direction normal to its axis. Specifically, the cast unit from which Figure 4 was drawn was one and threeeighths inches high and one and three-eighths inches maximum diameter. Minor changes in the form of the unit may be made to facilitate casting or fabrication. It may, for instance, be desirable under some circumstances to make the figure slightly tapered to aid withdrawal of the unit from a mold.

It will be apparent that the ratio of surface area to weight of consumable metal may be varied by making the grooves deeper or shallower,

.of Figure 4 is one of the most satisfactory tried,

I may use various other grooved units in combination with a perforate, insoluble receptacle. In Figure 5, for instance, there is seen a grooved, cylindraceous anode unit with a largerv number of grooves. This unit is hollow, having a hole thru its center, but the use of hollow anode units is not, per se, a part of this invention.

In Figure 6 there is seen a modified grooved anode unit on which the grooves are directed in a spiral manner. In addition to increasing the surface area of the figure. the grooves tend to cause a rotation of the anode unit as it moves downwardly in a receptacle.

In Figure 7 there is seen a grooved anode unit on which the grooves are of a different shape than in the other figures. This anode unit tends to stick slightly in a basket such as that of Figure 1. It is noted that, surprisingly enough, the grooved figures retain their shape as they diminish in size. A cast, cadmium anode unit such as the one shown in Figure '1 had an original size of: height two inches, outside diameter two inches, center core diameter about three-fourths inch, thickness of teeth" three-eighths inch. After about thirty-eight hours of electroplating the size was: height one and one-fourth inches, outsidediameter one and five-eighths inches, center core diameter about five-eighths inch, thickness of "teeth about one-eighth inch. After eighty hours of electroplating the figure was about one and one-eighths inches high and about threeeighths inch in diameter. Even after this great decrease in size, the grooves were about oneeighth of an inch deep on the surface.

While I prefer to use grooved cylindraceous units, I may use numerous other grooved figures. In Figure 8, for instance, there is shown a grooved cone. The grooves preferably extend longitudinally of the figures, but not necessarily. In Figure 9 there is shown a modified anode unit which has circumferential grooves. A

As a practical matter, the advantages of my invention are best realized with a grooved, cylindraceous unit the greatest outside dimension of which does not greatly exceed three times the smallest outside dimension. Specifically, I prefer to employ a grooved, cylindraceous anode unit the greatest outside dimension of which does not greatly exceed twice the smallest outside dimension. More specifically, I prefer to use a grooved, cylindraceous anode unit the height of which is substantially equal to its greatest diameter. Also as a practical matter, an anode unit should preferably be of such size and proportions that it could be inclosed in a sphere two or three inches in diameter.

The anode units are, of course, made of the metal which is to be electro-deposited. They may, for instance, be made of zinc, cadmium, zincmercury alloys, cadmium-mercury alloys, copper, and the like. I have found the anode units particularly desirable in connection with cadmium plating, and accordingly, my invention is particularly directed to the use of cadmium, grooved, cylindraceous anode unit the greatest outside dimension of which does not greatly exceed three times the smallest outside dimension. It is noted that the anode units of Figures 4, 5, 6 and 7 bear a superficial resemblance to gears.

While I have shown a number of specific forms of baskets and anode units, I do not intend to be limited thereby. The baskets may take various forms, and the grooved anode units, likewise, may assume various shapes and proportions. The anode units may also be varied in minor respect to facilitate casting or fabrication.

The scope 01' my invention will be more clearly apparent from the following claim.

I claim: a

An anode for use in electrodeposition comprising a plurality of spaced, vertical, insoluble 'wires 10 which define a vertical tube, the said tube being closed at its lower end and open at its upper end, the basket thus constructed containing a substantially single column of consumable, grooved, cylindraceous anode units which bear a superiicial resemblance to a gear whereby the teethlike portions of said units tend to engage the vertical wires, and whereby the units descend freely and without wedging in the basket walls. 

